Question

Pick whether each statement is true or false.


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A liquid is more compressible than a gas.
-- My Answer: False
A fluid can do work on a solid object.
-- My Answer: True
Both liquids and gasses are fluids.
-- My Answer: True
The force exerted by a fluid always acts perpendicular to the solid surface it is in contact with.
-- My Answer: False


I would love to know if my answers are correct. Thanks!

Answer 1

The force exerted by a fluid always acts perpendicular to the solid surface it is in contact with.
-- My Answer: False
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Well, this is true at zero speed where there is no friction. All you have is pressure forces, normal to boundaries. However in the real world at speed, for example pressure losses in a narrow pipe, you are indeed correct.